Spraying type etching machine for printing plates



June 6, 1967 c;A G. LINK 3,323,528

SPRAYNG TYPE ETCHNG MACHINE FOR PRINTING PLATES Filed oct. 23, 1965 5 SheeJoS--Sheffl 1 June s, 1967 G. G. LINK 3,323,528

SPRAYING TYPE ETCHING MACHINE FOR PRINTING PLATES Filed Oct. 23, 1965 3 Sheets-Sheet E Mar/76W June 6, 1967 G. G. L INK 3,323,528

SPRAYING TYPE ETCHING MACHINE FOR PRINTING PLATES Filed Oct. 25, 1965 3 Sheets-Sheet 5 10 T0 fal United States Patent O 3,323,528 SPRAYING TYPE ETCHING MACHINE FOR PRINTING PLATES George G. Link, 8900 Greenbrar Piace, Buena Park, Calif. 90620 Filed (Bet. 23, 1965, Ser. No. 502,848 3 Claims. (Cl. 134-57) The present invention relates generally to an improved machine for making printing plates, and it relates more particularly to an improved machine of the spraying type for producing such printing plates by an etchant.

It is usual to provide pre-curved printing plates of magnesium, zinc, plastic or other appropriate material. These plates are subsequently used, for example, on the dry offset type of printing machine, and the wrap aroun printing press.

The impressions an the pre-curved printing plate are made lby using any known photo-engraving process. In such a process, a surface of the printing plate is selectively coated by a photo-resist. The coated plates are then placed in the etching machine of the present invention, so that the exposed areas may be acid-etched. In this manner, the type characters and screen area making up the information on the printing plates are produced as high relief areas on the surface of the plate.

Problems have been encountered in the past in the acidetching of printing plates. The most serious problem probably has been that of under-cutting of the high reiief areas by the etchant. It is most important that the walls of these high relief areas be as nearly vertical as possible. Otherwise, ink and dirt will lodge in the resulting recesses, all of which detracts from the sharpness of the final printed material.

An important object of the present invention is to provide an improved spraying type of etching machine for p engraving printing plates, which machine is constructed to operate in a manner such that under-cutting of the high relief areas of the printing plates is reduced to an `absolute minimum.

Another object of the invention is to provide such an improved spray etching machine which is simple and economical in its construction, and which is extremely easy to operate.

Yet another object of the invention is to provide such an improved spray etching machine which is iiexible in that it can be easily modified to treat printing plates in a wide range of sizes and shapes.

The improved machine, in the embodiment of the invention to be described, includes a drum-like plate holder which is mounted in a tank for rotation about a horizontal axis. The plate holder, in a constructed embodiment of the invention, for example, is capable of handling printing plates from two and five/ eighths inches to twenty and one/half inches in diameter, and Oflengths up to eighty inches across the cylinder.

The above mentioned drum-like plate holder can be rotated at any desired speed, and the direction of rotation can be reversed. The forward and reverse rotation of the plate holder can be controlled so as to produce high relief areas with vertical side walls, or with side walls of any desired angle.

An automatic water-cooled refrigeration system is provided in the constructed embodiment of the invention. This refrigeration system can be operated in conjunction with a heating system so as to establish the temperature of the etchant at any desired pre-set [level and maintain the set temperature throughout the operation.

The constructed embodiment of the invention provides over a thousand sprays of the etchant to produce a uniform treatment over the entire surface of the workpiece. This assures uniform, clear-cut etching over the entire surface of each of the workpieces supported on the plate holder, and this etching takes place simultaneously over all the workpieces.

As will be described, the etchant is placed in the tank, and it is pumped through the spray pipes. It is then collected again at the bottom of the tank and is cooled by the coils of the refrigeration system, so that it can be maintained at the selected temperature. The etchant is then recirculated through the spraying pipes. The pressure and flow of the etchant sprays may be controlled, as Will be described.

The features of the invention which are believed to be new are set forth in the claims. The invention itself, however, together with further objects and advantages thereof, may best be understood by reference to the accompanying drawings, in which:

FIGURE l is a perspective view showing the various details of the spray etching machine of one embodiment of the present invention;

FIGURE 2 is an enlarged view, with respect to FIG- URE 1, of a control panel included in the machine of FIGURE 1;

FIGURES 3, 4 and 5 are sectional views of the machine taken respectively along the lines 3-3, 4--4 and 5 5 of FIGURE 1;

FIGURES 6 and 7 are cross-sectional views of the machine, showing the manner in which the internal components may be easily modified so as to handle workpieces of diiferent shapes and sizes;

FIGURE 8 is a perspective view of a circulating system for the etchant, which is used in conjunction with the etchant tank in the machine of FIGURE l, and which serves to circulate the etchant under pressure to the tubular spraying members which are also located in the etchant tank above the normal level of etchant therein; and

FIGURE 9 is a perspective view of a typical pre-curved printing plate, suitable for treatment by the machine of the present invention.

The mechanism shown in FIGURES 1-5 includes a tank 10 which has a cylndrical configuration and which has an open top. The tank may be formed of anodized aluminum, for example, so as to be high-ly resistant to the acid etchant which is placed in the tank.

A pair of arcuate manifolds 12 are disposed in the tank (see FIGURE 4), the manifolds 12 being composed, for example, of aluminum and, themselves being perforated to provide etchant sprays.

A plurality of perforated pipes 14 extend from the manifolds 12 on each side of the tank 10 and horizontally along the length of the tank. The manifolds l2 themselves are apertured, as noted above, so that additional etchant sprays are emitted from them.

A drum-like plate holder `16 is removably supported in the tank 10 on a pair of shackles 13 and 2li for rotation about a horizontal axis. The plate holder 16 has a central shaft 22. An overhead traveling crane, indicated generally as 25, may be provided, and this crane serves to carry the plate holder from a supporting table 23 to the tank lll.

The crane then serves to lower the plate holder 16 through the open top of the tank and onto the shackles 18 and 2t). The shackles support theA plate holder for rotation about the horizontal axis within the tank. The apertured manifolds 12` and apertured pipes 14 are arranged so that they may be disposed in an arcuate manner to be uniformly displaced from the surface of the plate holder 16. This displacement, for example, may be of the order of three inches.

A cover 30` is provided which is hinged to the tank 10, and which may be closed when the plate holder is in place in the tank 10. An exhaust system 32 including an appropriate exhaust fan is provided for removing 3 the fumes from the interior of the tank when the machine is in operation.

It will be appreciated that the drum-like plate holder 16 is first placed on a pair of brackets 34 and 36 on the table 28, and the pre-curved printing plates 31 (FIG- URES 1 and 9), suitably masked, are aixed to the plate holder. Then, the plate holder 16 is moved by the crane 26 and lowered down into the tank 10, as described above. The cover 30 is then closed. Prior to that, an appropriate quantity of suitable acid etchant solution (of any known composition) is poured into the tank 10. The apertured pipes 14 are disposed above the normal level of the etchant solution, as mentioned above.

The machine includes a drive motor 40 which is coupled to the shackle 20, and which serves to rotate the drum-like plate holder 16 about the horizontal axis. An appropriate worm gear, or other element, may be provided so that the drum will move longitudinally back and forth a pre-set distance as it rotates. The speed yof the motor is controlled, for example, by a manually `adjustable knob 42 on the control panel 46 of the machine. In addition, the motor 40 is controlled by a switch 44 so that it may rotate either in the forward or reverse direction.

A refrigeration system, designated generally as 47, is provided at one end of the tank 10, and this system includes refrigeration coils 48 disposed at the bottom of the tank. A temperature control 50 (FIGURE 2) is provided, so that the etchant solution circulated in the system may be maintained at any desired temperature.

In addition, a heating element (not shown) may be provided when the ambient `temperature conditions are low, so that an appropriate control may be exerted both on the heating element and on the refrigeration system to maintain the desired temperature. In the constructed embodi-ment, a 3 kilowatt tubular heating element was provided, and a thermostat control for both the refrigeration system and the heating element was also provided in order that the desired pre-set temperature of the etchant could be maintained.

In the constructed embodiment of the invention, the drive motor 40 for the plate holder 16, was a one/sixth horsepower, 110 volt, direct current, variable-speed motor. The motor for the compressor of the refrigeration system, on the other hand, was a one/half horsepower, 220/440 volt, 60 cycle, `three-phase motor.

The pre-curved printing plates 31, as mentioned, may be composed of zinc, magnesium, plastic, or any other appropriate material. These plates are selectively treated, prior to `being etched in the machine, by any known photo-engraving process.

As shown in FIGURE 4, the pair of arcuate manifolds 12 are coupled to a T-shaped manifold 60 which, in turn, is coupled to the outlet of a pump 62. The T- shaped manifold 60 may be composed, for example, of stainless steel.

The pump 62, as best shown in FIGURE 8, is formed as a unit with its outlet 66 being provided with an appropriate ange which may be coupled to the T-shaped manifold 60. The inlet `68 of the pump also has an appropriate flange which is fastened to the bottom of the tank and which surrounds an opening in the bottom tof the tank.

A -motor 70` is coupled to the pump assembly and drives the pump. When the motor is energized, the pum-p 62 draws the etchant solution from the -bottom of the tank 10 through its inlet 68 and discharges the solution under pressure through its outlet 66. The solution then passes into the manifold 60` and into the apertured manifolds 12 and to the apertured pipes 14.

The etchant issues as a spray from the pipes and from 'the manifolds 12. During the operation of the mechanism, the etchant is continuously circulated from the tank to the spray members and back to the tank. The refrigeration coils 48 (and heating element) maintain the 4 etchant solution at a preset temperature as it is circulated through the system. The speed of the motor 70 may be controlled by an appropriate control knob 72 on the control panel 46 (FIGURE 2), so that any desired spraying pressure may be achieved.

The mechanism also includes a timer which may be set by the knob 74 `on the control panel 46 (FIGURE 2), and which serves to reduce the pump motor 70 to an idler speed after a predetermined time interval, so as to terminate the spraying operation.

As shown in FIGURE 6, in order to modify the equi-pment, the apertured spraying pipes 14 which pass through the manifolds 12, and the manifolds 12, may be removed, leaving only the apertured spraying pipes 14 which pass through the T-shaped manifold 60.

A flat plate holder may be provided for supporting at workpieces, and the flat plate holder may be reciprocated `over the sprays issuing up from the remaining spraying members 14. Also, if so desired, additional apertured spraying pipes 14 extending along the tank 10 in alignment with the illustrated spraying members 14 may be provided.

In the embodiment of FIGURE 7, an arcuate spraying member 84 is coupled to the manifold 60, and this member directs sprays towards the center, so that a cylindrical workpiece 86 of extremely small diameter, may be supported for treatment at the center, as shown.

The invention provides, therefore, an improved and highly exible spraying machine for etching printing plates, and the like. The machine of the invention is simple and economical in its construction, and is extremely easy to operate.

The machine of the invention provides for the forward and reverse movement of the workpiece in the etchant sprays, so that sharp, vertical walls may be obtained for the high relief areas.

It will be appreciated that while particular embodiments of the invention have been shown and described, modifications may be made. It is intended in the claims to cover all the modifications which come within the scope of the invention.

What is claimed is:

1. Apparatus for etching pre-curved printing plates with an etchant solution including: a tank into which the etchant solution is introduced to a selected level; a drum-like plate holder for the pre-curved printing plates; shackle means for removably mounting said drum-like plate holder within said tank for rotation about a predetermined axis; manifold means comprising a pair of perforated `arcuate support members mounted within said tank; a plurality of tubular spraying members mounted in said tank above the normal level of etchant solution in said tank and configured as perforated pipes coupled to said manifold means and extending along the length of said tank above the selected level of said etchant solution and disposed in mutually spaced relationship and in an arcuate placement about said predetermined axis to be displaced from the surface of said drum-like plate holder a substantially uniform radial distance; drive means coupled to said plate holder for driving said plate holder in either of two predetermined directions, said drive means including a Variable speed drive motor coupled to said shackle means for rotating said drum-like plate holder at selectively variable speeds about said predetermined axis; means coupled to said tank for circulating etchant solution from said tank under pressure to said tubular spraying members, sai-d lastnamed means including a circulating pump having an inlet and an outlet, conduit means coupling the inlet of said pump to the bottom of said tank, further conduit means coupling the outlet of said pump to said manifold means, and variable speed drive means for said pump to cause said pump to circulate the etchant solution under various controlled pressures through said manifold 5 and into said perforated pipes to be ejected through the perforations thereof as etching sprays `directe-cl to the surface of said drum-like holder; temperature control means dis-posed in said tank below the selected level of said etehant solution for maintaining said etchant solution at a predetermined temperature.

2. The apparatus dened in claim 1 in which said tank has a cylindrical configuration and an open top to permit the insertion and removal of said drum-like plate holder.

3. The apparatus dened in claim 1 in which said tank and pipes and manifold means are composed of anodized aluminum.

References Cited UNITED STATES PATENTS 2/1963 Guenst 134--58 X 5/1963 Sigler 134-148 X 12/1963 Bock et al. 156--345 2/1964 Boitos l5614 2/1966 Ruttan et al 134--148 X FOREIGN PATENTS 10/1909 Great Britain.

CHARLES A. WI'LLMUTH, Primary Examiner. R. L. BLEUTGE, Assistant Examiner. 

1. APPARATUS FOR ETCHING PRE-CURVED PRINTING PLATES WITH AN ETCHANT SOLUTION INCLUDING: A TANK INTO WHICH THE ETCHANT SOLUTION IS INTRODUCED TO A SELECTED LEVEL; A DRUM-LIKE PLATE HOLDER FOR THE PRE-CURVED PRINTING PLATES; SHACKLE MEANS FOR REMOVABLY MOUNTING SAID DRUM-LIKE PLATE HOLDER WITHIN SAID TANK FOR ROTATION ABOUT A PREDETERMINED AXIS; MANIFOLD MEANS COMPRISING A PAIR OF PERFORATED ARCUATE SUPPORT MEMBERS MOUNTED WITHIN SAID TANK; A PLURALITY OF TUBULAR SPRAYING MEMBERS MOUNTED IN SAID TANK ABOVE THE NORMAL LEVEL OF ETCHANT SOLUTION IN SAID TANK AND CONFIGURED AS PERFORATED PIPES COUPLED TO SAID MANIFOLD MEANS AND EXTENDING ALONG THE LENGTH OF SAID TANK ABOVE THE SELECTED LEVEL OF SAID ETCHANT SOLUTION AND DISPOSED IN MUTUALLY SPACED RELATIONSHIP AND IN AN ARCUATE PLACEMENT ABOUT SAID PREDETERMINED AXIS TO BE DISPLACED FROM THE SURFACE OF SAID DRUM-LIKE PLATE HOLDER A SUBSTANTIALLY UNIFORM RADIAL DISTANCE; DRIVE MEANS COUPLED TO SAID PLATE HOLDER FOR DRIVING SAID PLATE HOLDER IN EITHER OF TWO PREDETERMINED DIRECTIONS, SAID DRIVE MEANS INCLUDING A VARIABLE SPEED DRIVE MOTOR COUPLED TO SAID SHACKLE MEANS FOR ROTATING SAID DRUM-LIKE PLATE HOLDER AT SELECTIVELY VARIABLE SPEEDS ABOUT SAID PREDETERMINED AXIS; MEANS COUPLED TO SAID 